I. Field of the Invention
The present invention relates to subscriber authentication in a wireless communication system. More particularly, the present invention relates to subscriber authentication in a wireless communication system where a group of subscribers share a set of modems.
II. Related Art
To prevent fraud and theft of wireless communication services and to properly bill the subscribers of a wireless communication service, wireless communication service providers (such as cellular telephony providers) have created a mechanism for authenticating their subscribers. This mechanism relies on the fact that each subscriber in the system has unique authentication information (UAI) for each transceiver owned by the subscriber.
This authentication information is necessary to gain access to a wireless communication system. In this way, the authentication information is somewhat analogous to a personal identification number (PIN) used for gaining access to one""s checking account through an automated teller machine.
Each subscriber""s authentication information consists of static authentication data and dynamic authentication data. An electronic serial number (ESN) and a mobile identification number (MIN) are two examples of static authentication data. Shared secret data (SSD) is an example of dynamic authentication data. Static authentication data, as its name implies, remains constant over time. On the other hand, dynamic authentication data may be altered while a subscriber is actively engaged in a call, while setting up a call or while registering with a base station, etc.
In traditional wireless communication systems, each subscriber has his own subscriber unit (or transceiver), such as a cellular telephone, and each subscriber is responsible for paying for all calls made from their cell phone. Further, each subscriber unit has a modem coupled to an antenna for transmitting radio frequency (RF) signals to and receiving RF signals from a base station within the wireless communication system. Thus, in conventional wireless communication systems there is a one-to-one relationship between modems and subscribers. Because of this one-to-one relationship, a subscriber""s unique authentication information is stored in the modem within the subscriber""s cell phone. By storing the authentication information in the subscriber""s modem, the modem can perform the authentication process in a manner that is transparent to the subscriber, and the modem can update and maintain the subscriber""s dynamic authentication information as necessary. Consequently, the subscriber need not trouble himself with having to maintain his authentication information.
However, in certain wireless communications systems (such as in a Concentrated Subscriber System described later herein) there is not a one-to-one relationship between subscribers and modem systems. In such a system it is desired that the authentication process be transparent to the subscribers in the same manner that the authentication process is transparent to the subscribers in a system where there is a one-to-one correspondence between subscribers and modem systems.
What is needed, therefore, is a system and method for transparently providing access to a wireless communication service where there is not a one-to-one relationship between subscribers and modems. Further, the system and method should be compatible with existing wireless communication systems.
The present invention overcomes the above identified problem. In one aspect the invention provides a method for transparently providing access to a wireless communication service to a group of subscribers who share a set of modems, where each subscriber in the group is provided with a subscriber unit and each subscriber in the group is associated with static and dynamic authentication information.
In one embodiment the method includes the steps of: (a) detecting the activation of one of the subscriber units; (b) selecting a modem from the set of modems; (c) coupling the activated subscriber unit with the selected modem, thereby enabling traffic to flow between the activated subscriber unit and the selected modem; and (d) providing dynamic authentication information to the selected modem, wherein the dynamic authentication information provided to the selected modem is the dynamic authentication information associated with the subscriber to which the activated subscriber unit is provided.
In another embodiment the method includes the steps of: (a) detecting an incoming call addressed to one of the subscribers in the group; (b) determining a called subscriber, wherein a called subscriber is the subscriber in the group to which the incoming call is addressed; (c) selecting an available modem from the set of modems; (d) coupling the subscriber unit provided to the called subscriber with the selected modem, thereby enabling traffic to flow between the subscriber unit and the selected modem; and (e) providing dynamic authentication information to the selected modem, wherein the dynamic authentication information provided to the selected modem is the dynamic authentication information associated with the called subscriber.
Advantageously, either embodiment may further include the steps of storing in a database the dynamic authentication information associated with each subscriber in the group; storing in the selected modem the dynamic authentication information provided to the selected modem; modifying the dynamic authentication information stored in the selected modem in response to the selected modem receiving an update command message from a base station; storing the modified dynamic authentication information in the selected modem; and storing the modified dynamic authentication information in the database. In this manner, the dynamic authentication information stored in the database is updated whenever an update is received by a modem.
Additionally, the method according to either embodiment may further include the steps of storing in each of the modems the static authentication information associated with each subscriber in the group.
The invention also provides a concentrated subscriber system. The concentrated subscriber system according to one embodiment includes a transceiver system for transmitting radio wave frequency signals to and receiving radio wave frequency signals from a base station; a set of modems, wherein each modem in the set is coupled to the transceiver system; a set of subscriber units, wherein each subscriber unit is associated with unique authentication information; a switch coupled to each of the modems and coupled to each of the subscriber units; a control system in communication with the switch and each of the modems; and a database for storing authentication information, wherein the database is accessible to the control system. The control system determines an available modem from the set of modems when one of the subscriber units is activated. Further, the control system directs the switch to connect the activated subscriber unit with the available modem, retrieves from the database authentication information associated with the activated subscriber unit, and provides the available modem with the retrieved authentication information. In this manner, the authentication information associated with the activated subscriber unit is provided to the modem that is handling the call. Consequently, the modem handling the call can transparently authenticate the subscriber unit in the same manner as in a conventional wireless communication service.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.